大跨度公铁两用斜拉桥地震易损性及风险分析

发布时间：2018-01-08 05:30

本文关键词：大跨度公铁两用斜拉桥地震易损性及风险分析　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：大跨度公铁两用斜拉桥,其结构相对普通桥梁要复杂,由于其跨越能力强,在大跨度桥型方案比选时候往往受到青睐。然而,我国是一个地震多发的国家,几乎每年都有大大小小的地震发生,且对于大跨度斜拉桥的地震易损性及其地震风险的研究目前尚处初级阶段,更没有比较全面的规范或经验可循。基于上述原因,文章以某大跨度公铁两用斜拉桥为工程背景,结合目前已有斜拉桥地震反应和易损性的研究现状,参照一般简支梁、连续梁和高墩刚构桥的地震易损性和风险分析的方法,提出该桥的损伤指标,选择合理易损性分析的方法,对该桥梁进行大跨度斜拉桥地震易损性和风险分析。通过对高墩、高塔斜拉桥结构进行纵、横向地震易损性和风险分析,得出研究结论,为今后此类研究提供一定参考。文章的主要研究内容概括如下:(1)以曲率作为控制参数,定义斜拉桥主塔和辅助墩、过渡墩等高塔高墩结构的损伤指标;以墩梁相对位移定义过渡墩、辅助墩支座的损伤指标。(2)以实际大跨度斜拉桥为算例,基于OpenSEES软件建立斜拉桥有限元模型,并且阐述各构件用何种单元模拟,最后用桥梁专用软件建立Midas模型对OpenSEES有限元模型进行验证,证明模型建立的正确性。(3)选择20条符合场地特征的地震波,以PGA(地震峰值加速度)为参数,同时考虑p-△效应,分别进行单条地震波IDA分析和多条地震波弹塑性时程分析,得到沿墩(塔)高的纵、横向的轴力和曲率分布,从而来确定易损性分析控制截面。(4)考虑地震动的不确性,分别输入20条地震波进行IDA分析,统计处理计算结果,建立大跨度斜拉桥以PGA为变量的控制截面概率地震需求模型。(5)对大跨度斜拉桥主要受力构件(主塔、塔横梁、辅助墩、过渡墩、支座)易损性分析。比较分析结果,针对斜拉桥各构件的易损部位和各构件的损伤次序等进行分析探讨。(6)研究我国不同烈度地区的地震危险性,根据易损性的分析结果和风险分析表达式,对大跨度公铁两用斜拉桥进行概率地震风险分析,分析风险分析结果,为以后研究提供参考。
[Abstract]:The structure of large-span double-purpose cable-stayed bridge is more complicated than that of ordinary bridge. Because of its strong span ability, it is often favored in the comparison of large-span bridge scheme. However, China is a country with earthquake. Almost every year, large and small earthquakes occur, and the study of seismic vulnerability and seismic risk of long-span cable-stayed bridges is still in the primary stage. Based on the above reasons, this paper takes a large-span double-purpose cable-stayed bridge as the engineering background, combined with the existing research status of seismic response and vulnerability of cable-stayed bridge. Referring to the methods of seismic vulnerability and risk analysis of simple supported beam, continuous beam and rigid frame bridge with high piers, the damage index of the bridge is put forward and the reasonable vulnerability analysis method is selected. The seismic vulnerability and risk analysis of the long-span cable-stayed bridge are carried out. Through the longitudinal and lateral seismic vulnerability and risk analysis of the tall pier and tall tower cable-stayed bridge structure, the research conclusions are obtained. The main contents of this paper are summarized as follows: (1) take curvature as the control parameter, define the damage index of the tall pier structure of cable-stayed bridge, such as main tower, auxiliary pier, transition pier, etc. Taking the relative displacement of pier beam as the definition of transition pier and the damage index of auxiliary pier support, taking the actual long-span cable-stayed bridge as an example, the finite element model of cable-stayed bridge is established based on OpenSEES software. At last, the Midas model is established by the bridge software to validate the OpenSEES finite element model. The correctness of the model is proved. (3) selecting 20 seismic waves that accord with the site characteristics, taking PGA (earthquake peak acceleration) as the parameter, and considering the p- effect at the same time. IDA analysis of single seismic wave and elastic-plastic time-history analysis of multiple seismic waves are carried out, and the axial and transverse axial force and curvature distribution along the height of pier (tower) are obtained. In order to determine the vulnerability analysis control section. 4) considering the uncertainty of ground motion, 20 seismic waves were input to IDA analysis, and the results of statistical processing were calculated. The probabilistic seismic demand model of long-span cable-stayed bridge with PGA as variable is established. The model is applied to the main components of long-span cable-stayed bridge (main tower, tower beam, auxiliary pier, transition pier). Comparing the results of the analysis, the seismic risk of different intensity areas in China is studied by analyzing the vulnerable parts of cable-stayed bridge and the damage order of each component. According to the results of vulnerability analysis and the expression of risk analysis, the probabilistic seismic risk analysis of large-span double-purpose cable-stayed bridge is carried out, and the result of risk analysis is analyzed, which provides a reference for future research.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U442.55;U448.27

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